Bright spots in solar's future?

There's nothing like a mega blackout to recharge public interest in residential energy alternatives. Not long after the lights and air conditioning went out in the extensive electric-grid failure last month, many homeowners began wondering: Whatever happened to solar energy?

Home Power magazine, which focuses on renewable energy, saw a surge in online traffic, and Richard King, the US Department of Energy's solar guru, kept getting calls from people who sought solutions because they didn't want to lose power again.

Homeowners feel they can't afford to be without their basement sump pump or home office for even a few hours, much less days. And their concern escalates when Ol' Man Winter is howling at the door and the furnace is stone-cold silent.

Not surprisingly, many look to the sky and wonder if solar should be in their energy future. Home Power magazine estimates that 147,000 American homes run solely on solar electricity, and the Department of Energy says about 1.1 million homes use solar power of some kind.

Still, it's safe to say that most people consider solar an infant on the energy landscape, just beginning to find its way.

Whether as a backup, supplemental, or main energy supply, however, it holds intriguing potential, even if it's still far more costly than most people would like.

The following questions and answers help summarize where residential solar has been, is now, and may be heading.

Why has solar been slow to catch on?

It got off to a shaky start in the 1970s, when escalating energy prices led many people to install solar hot-water systems in their homes. Much of the equipment, however, was unreliable and unattractive.

What has changed to make solar a more appealing option?

Partly it's growing public interest in exercising more control over fluctuating energy costs. Solar is environmentally attractive, too. The recent blackout has alsospurred inquiries.

What's new?

In the past 10 years, the big breakthrough has been the development of inverters that take the direct-current (DC) electricity generated by photovoltaic cells and convert it into alternating-current (AC) electricity, or common household current.

This has opened the door to connecting domestic solar systems to the utility electrical grids in 38 states. The flow of energy can be measured into or out of the house, so that during daylight hours photovoltaic (PV) panels may actually feed surplus power onto the grid, causing the meter to spin backward, lowering the electric bill.

Industry standards have also improved since the 1970s. "Any major manufacturer of a PV panel has to have a minimum of a 20-year warranty," says Don Bradley, a solar home builder in Philadelphia.That's a longer warranty than on other components in the house, he adds.

What are the advantages of solar electricity?

It allows you to be your own producer of electricity, with no noise, no pollution, and no moving parts. It also is of higher quality than a utility company generally provides, says Richard Perez, publisher of Home Power magazine. For homeowners, this translates into appliances that are cooler running, more efficient, and have longer-lasting motors.

Does having solar electric mean your home will always have power, even during a blackout?

It depends on what kind of system you have. Some homes have systems that are not connected to the local utility's electric grid at all. As a result, they won't be affected by power outages.

When a homeowner uses solar power, but also supplements it with power from the grid, that additional electricity is lost in a blackout. To enjoy uninterrupted service, people on the grid can equip their system with a battery backup system.

What is the primary obstacle to wider acceptance of solar energy?

Price. The upfront costs of solar energy, can be jarring - often $10,000 to $20,000 or more.

The cost of producing electricity from sunlight is approximately two to four times as expensive as from coal or gas, although in the past two decades, the price per kilowatt hour has come down from $1 to about 20 or 30 cents.

Solar water heating ordinarily costs between $3,000 and $10,000, with most systems about $4,000 price range.

Why is the price of solar so variable?

Every house is different, and lifestyles vary, too. Plus, there's quite a range of financial incentives offered by state governments.

For an existing house, the expenditure is comparable to buying a good previously owned car, Mr. Perez says, but some people are looking for a used Chevy and others a used Mercedes.

BP Solar, a manufacturer of photovoltaic products and systems, offers an online cost estimator, using a person's ZIP Code, current energy usage, and preferred system capacity to provide a ballpark guesstimate. (See www.bpsolar.com/home solutions/solarsavingsestimator. cfm.)

States that offer significant financial incentives to bring the price down include California, New York, New Jersey, Pennsylvania, Colorado, Minnesota, and North Carolina.

Where does solar make the most sense geographically?

The amount of sunlight is only one factor, says Joel Gordes of Environmental Energy Solutions. New York State, he believes, is prime solar territory because of tax credits, rebates, and loan programs, as well as potential savings on energy bills.

"New York has very high electric rates, so it makes sense economically to do a solar system," he explains. Utility customers in New York pay 13 or 14 cents per kilowatt hour, well above the national average of about 8 or 9 cents. This helps offset the fact that New York is less sunny than Arizona, where coal is plentiful and electric rates are only 7 or 8 cents per kilowatt hour.

How can the large upfront cost of solar be made more palatable?

Rolling it into a 30-year house mortgage helps, and lenders seem more inclined these days to finance solar this way.

When building a new home, Mr. Bradley suggests that instead of spending $8,000 on fancy kitchen cabinets, marble countertops, or a cultured-stone fireplace, some people may want to put that money into a solar system.

Can a do-it-yourselfer install a photovoltaic system?

Although the technology has been simplified, installation of even plug-it-in systems is not for amateurs.

"You still need to know where to plug it in, it's still carrying voltage, you still have to work on a roof," Bradley says. "You still need to have the absolute right tools, and you need a certified electrician to interact with the grid, and that's the same thing as with a central air- conditioning [system]."

Home Depot now sells residential electric solar-power systems in selected stores, but they're offered as part of a full-service program that includes financing, installation, and service.

Can solar be used for central heating or air conditioning, or is it limited to appliances?

It's capable of handling all a home's electrical needs. Of course, the more you ask of a solar system, the bigger (and more expensive) it will need to be.

Doesn't solar equipment spoil the look of a house?

Manufacturers are working to develop flatter and less obtrusive panels. One company has come out with solar shingles that use thin-film technology to make a lightweight, flexible roofing product. These dark blue shingles can be nailed or screwed directly to plywood sheathing, just as asphalt shingles can. However, experts say, they are less efficient than traditional panels, so more roof surface must be covered. Plus they carry a premium price.

Solar laminate material can also be bonded to the metal roofs increasingly used in home construction.

How much repair and maintenance does solar-electric equipment require?

Very little, according to industry experts, because there are no moving parts and little that can break. Inverters remain the weak point in most systems and sometimes need to be repaired or replaced.

Routine maintenance includes checking the water level of backup batteries and keeping the connections clean, hosing off solar panels, and, if there's a significant drop-off in electricity produced, checking for loose wires, a faulty panel, or perhaps shade.

If a person doesn't want to install panels but still wants to take advantage of solar, does adding a solar greenhouse or sunroom make sense?

Passive solar (which includes sunrooms) is definitely worth looking into, since it's considered the most cost-effective option. If done properly, with the right orientation and siting, a passive solar greenhouse can be a tremendous asset. But done incorrectly it can be an "absolute nightmare" in terms of energy efficiency and comfort, says Bradley. If the space doesn't get enough sun, it can freeze in winter. Too much sun and it cooks in summer.

Other passive-solar options include energy-efficient glass, insulated shades, and heat- absorbing walls.

Have solar hot-water systems improved?

Yes. "They are one of the best-kept secrets in the industry," says Joe Wiehagen of the National Association of Home Builders Research Center. Quality has improved and the industry has standardized much of the technology. They're also highly efficient.